RE: LIN6 i-d for multihoming and mobility support

["marcelo bagnulo" <mbagnulo@ing.uc3m.es>]

Hi Fumio,

Some comments about this draft.

My main concern about this proposal is about the Mapping Agent

The mapping agent becomes a critical part since it is required to establish
the communication, so in a multi-homed environment, where do you place it?
do you place it in the multihomed site or in the isps? what happens if the
path to the MA is down? i guess that since one of the goals of multihoming
is the provision of a more resilient network, the inclusion of an additional
critical device must be very well justified and the potential failures of
such device must be studied in depth

Besides, the usage of a mapping agent introduces additional latency and
traffic since, if i understood it correctly, several new round trips are
required i.e. a query to the MA from the initiator and a reverse DNS query
and a direct DNS query and a MA query from the receiver is also required.
These are a lot of additional packets and time required to initiate the
communication

Finally, i really don't understand why the mapping agent is needed in the
multi-homed environment. I mean, i do understand that the MA is needed for
mobility, but i think it is not needed for multihoming. In the noid
proposal, the mechanism is similar (i think) but only the dns is used. This
is good because you don't add an additional critical device and you reduce
the packet exchanges (you don't have to query the MA)

Additionally, there are multiple issues that are not addressed in the draft
and that IMHO it would be important to understand how they can be addressed
when using LIN6 like ingress filtering (you claim that this is not an issue
but i disagree), address selection for initial contact (especially source
address selection and how is this compatible with the ingress filtering
solution that you are planning to use), failure detection (how do you know
that you have to change the address that it is being used, and how do you
know if you have to change the destination or the source address)
IMHO all this problems have to be addressed in order to obtain a complete
multihoming solution and an analysis about how LIN6 is compatible with
proposed solutions for these issues would be interesting.
Additionally, i think it would be interesting to include a descrition of how
lin6 can cope with the threats described in the threats draft. I mean, lin6
introduces the MA which is susceptible to be attacked. In the security
section, it is claimed that this solution is not less secure than MIPv6, but
no comments are included for the multi-homing environment where no MIPv6 is
used.

Regards, marcelo

> -----Mensaje original-----
> De: owner-multi6@ops.ietf.org [mailto:owner-multi6@ops.ietf.org]En
> nombre de Fumio Teraoka
> Enviado el: martes, 30 de diciembre de 2003 10:25
> Para: multi6@ops.ietf.org
> Asunto: LIN6 i-d for multihoming and mobility support
>
>
> Hi all,
>
> I have just submitted draft-teraoka-multi6-lin6-00.txt that describes
> multihoming and mobility support based on LIN6. Sec.8 discusses
> the features of LIN6 based on RFC3582.
>
> The draft is available from the following URL:
>
> http://www.tera.ics.keio.ac.jp/person/tera/multi6/draft-teraoka-mu
lti6-lin6-00.txt

Comments are welcome.

Fumio Teraoka